Carew transitioned from 2B to 1B in September of his age 29 season (1975). According to BB-Ref, he had been basically a league average defender. Bob Randall, the guy who replaced him, put up just 3.8 WAR player over < 5 years at 2B...

Back in 1967, Griffith had insisted that manager Sam Mele open the season with a Carew, a 21-year-old out of the Class A Carolina League, as his second baseman. Playing there, he was Rookie of the Year, was chosen for nine All-Star teams and was on his way to the fifth of seven batting titles in 1975.

The Twins had grumbled, mostly in private, about Carew’s ability to turn the double play after a knee injury incurred on a pivot cost him much of the 1970 season. This was a quarter-century before the “analytics’’ craze, when baseball men could convince themselves turning a double play was more important than having a hitting machine at second base.

The Twins had fantastic pivot man in Bobby Randall as Carew’s first replacement at second, but that .257 career average wasn’t quite Carew’s .334 in 12 years in Minnesota, now was it? Carew played 14 games at first base in September 1975, then spent the final 10 seasons (three here, seven in California) of his Hall of Fame career there. Early on, he was asked about the difference, talked of the baseball aspects and added: “You hear the wolves in the stands, too. They yell at everyone and about everything. As a second baseman, I wasn’t aware of that.’’

"The Twins had fantastic pivot man in Bobby Randall as Carew’s first replacement at second, but that .257 career average wasn’t quite Carew’s .334 in 12 years in Minnesota, now was it?" But the guys Carew replaced at first were John Briggs and Tom Kelly. Their combined average of around .200 was much farther removed from Carew's .334. Better defense at 2nd base and the offense replaced .200 average with Randall's .257. Pretty logical move.

I remember hearing that as an excuse/reason for the move, but I can't say I really saw it. I might not be quite an old enough old guy for the question (I was 10 at the time) and the only time I saw the Twins on TV was when they were on a national broadcast (Mon night or Sat afternoon) or when they played the Red Sox. And it wasn't a 60" HD screen, either. It was 19" black and white with fuzzy reception (before cable.)

Carew was a good fielder, but he did miss most of one season after getting injured on a double play pivot. As he became a great hitter, the feeling was that it would save his legs and put a better defender at second by moving him to first.

I remember him as stringer bell described. They didn't like the runners trying to take him out at second base. They use to go in a lot harder than they do now. Carew quit stealing home after Killebrew missed the sign and swung at the pitch.